This invention relates to a relief valve which provides for safe protection of such systems while allowing for their proper operation. More particularly it relates to a low pressure relief valve of elastomeric material and a method for relieving pressure in low pressure systems.
The use of a resilient, elastic and somewhat flexible material in the formation of the valve structure of a cap to a bottle or jar is disclosed in U.S. Pat. No. 2,486,364 and a self-disclosing dispensing head of resilient material for tubes and resilient containers in disclosed in U.S. Pat. No. 3,179,301.
U.S. Pat. No. 4,620,648 discloses a pressure response valve which includes an elastically deformable diaphragm having a plurality of non-intersecting non-meeting separate arcuate slits, each slit having a base which is intersected by at least one other slit, and each slit being out of intersecting relation with its own base.
The disclosed valve controls flow, especially of viscous fluids but does not control pressure. The disclosed valve operates by deflection of the deformable diaphragm in response to an outer directed force. This deflection causes a rotation of one portion of the diaphragm relative to the other portion of the diaphragm as it moves outwardly in response to the force resulting from the pressure differential. The diaphragm valve operates similarly to a helical spring. The diaphragm can be plastic or metal which indicates that the diaphragm is relatively thin.
Many expensive and sophisticated devises exist which relieve high pressure. Low pressures are defined here to be less than or equal to 100 psig. However, simple devices or valves for relieving low pressure are not readily available. Examples of fixed systems requiring low pressure venting are fuel and solvent storage tanks, large vessels anchored to foundations, small vessels attached to piping networks and piping networks all of which generally are part of an industrial or commercial process. Examples of movable systems requiring low pressure venting are casks, carboys and barrels containing various fluids having gas pressures or vapor pressures which could reach unsafe limits if the system is heated or agitated. It would be desirable to have a low cost, low pressure relief valve for relieving pressure in movable and fixed systems requiring low pressure venting.